by the Chemistry Core. These compounds will be designed as opioid agonists and bradykinin/dynorphin antagonists in order to produce potent and efficacious antinociception targeting the pathology of neuropathic pain while eliminating antinocicpetive tolerance. The Biochemical Core contains 7 aims that will test such novel compounds. The in vitro pharmacological data in particular will provide timely feedback to the Chemistry Core on the structure-activity relationship (SAR) to further inform chemistry design. The initial binding and functional characterization of all novel compounds (est. 20 to 50 compounds/year) is necessary and essential for target-based drug discovery. To identify lead compounds, we must evaluate their affinity at multiple opioid and bradykinin receptors, and their apparent biological activity at each of these receptors. Studies will include in vitro tissue assaysto determine agonist and antagonist activity as well as novel compound activity at calcium channles using calcium fluorimetric analysis in transfectd cells. We will use a number of in vivo animal models to identify whether such novel bi-functional compounds produce antinociception as well as antihyperalgesia in inflammatory and chronic pain states. Finally, in vivo studies will be performed to detemine whether such compounds will result in antinocicpetive tolerance. Overall, Studies will be performed to identify molecules with agonist activity at one receptor and concurrent antagonist actions at a second receptor. The biochemical core provides dedicated equipment, personnel and expertise in data analysis for the entire project. It serves to centralize the use and maintenance of shared equipment and the technical training of personnel to use these equipment, management and oversight of animal protocols required by IACUC and Radiation Control, as well as to ensure data and information sharing with the Chemistry Core and the other projects. The biochemical core will synergize with projects A, C and D by providing lead compounds to directly test their hypotheses. RELEVANCE (Seeinstructions): Inflammatory and chronic neuropathic pains are growing areas of unmet medical need. Clinically, chronic pain remains poorly controlled by available therapies and thus adversely impacts quality of life (Arner & Meyerson, 1988). One reason for this lack of effect is the absence of compounds that specifically target the pathology of neuropathic pain. The goal of the chemistry & biochemical core of this PPG are to synthesize and test compounds that result in potent and efficacious antinociception while eliminating tolerance. PROJECT/